Stair-climbing wheel chair



1966 R. K. BROWN ETAL 3,283,839

STAIR'CLIMBING WHEEL CHAIR 2 Sheets-Sheet 1 Filed March 2, 1965 INVENTO/PS RONALD K. BROWN JAMES G. BE/VEKE ATTO/P/VEV United States Patent 3,283,839 STAIR-CLIMBING WHEEL CHAIR Ronald K. Brown, 643 Buckeye St., Apt. 3, Redwood City, Calif., and James G. Beneke, 835 14th Ave., Menlo Parlr,Calif.

Filed Mar. 2, 1965, Ser. No. 436,478 17 Claims. (Cl. 1808) This invention relates to a new and improved driven wheel arrangement enabling a wheel chair or similar device to climb or descend stairs or similar obstacles. Heretofore, various means have been devised to enable wheel chairs to climb stair-s, but these generally have been in the form of a continuous track or belt which engages only the corners Where the treads and risers of the stairs meet. The present invention uses an arrangement of a plurality oi? wheels, one of which rests on each stair tread as the device climbs or descends. Accordingly, the present invention provides a more positive and safer means for climbing or descending than that previously used.

A further feature of this invention is the fact that the same mechanism may be used for advancing the chair on level ground as for ascending or descending.

A particular feature of the invention is the fact that the mechanism is so constructed that when a barrier, such as a stairway, is encountered the chair automatically climbs or descends the impediment.

Another feature of the invention is the *fact that the mechanism which permits climbing the stairway also permits descending the stairway without major modification.

A principal advantage of the stair climbing wheel assembly hereinafter described is that it enables a vehicle to negotiate stairs or similar obstructions smoothly and without sliding or scraping. As hereinafter described in detail, the invention employs a plurality of wheels mounted on a spider rotatable about a central axis. A feature of the construction is that the spider does not'scrape against the corners of the stairs. It will further be understood that it is customary in the construction of Stairways and particularly common household wooden stairs to use an overhang or lip at the :forward edge of each tread projecting beyond the adjacent riser. The present invention provides means whereby the device does not catch or hang up on such overhang, but moves smoothly despite the obstacle created thereby.

A still further feature of the invention is the provision of means under the control of the'operator or automatic means to maintain the chair substantially level during ascending or descending.

Thus, a principal object of the present invention is to permit an unattended occupant freely to climb or descend stairs without danger of tipping and without substantial manual effort.

In one form of the invention the balancing means comprises a downwardly-outwardly projecting pivoted arm supported at its lower end by pluralities of rollers mounted on arms projecting from the axis of mounting. The arms rotate about the axis and the rollers also rotate about their own axes and this arrangement provides a particluarly effective means for supporting the chair or other vehicle against tipping and, at the same time, prevents the chair from catching or hanging on the overhanging lip of the stairs. Preventing the rollers from catching on the overhang may be augmented by using belts around some of the rollers, as hereinafter described in detail.

Although the present invention is illustrated and hereinafter described applied to a wheel chair, it will be understood that the mechanism is adaptable to other vehicles.

Other objects of the :present invention will become apparent upon reading of the following specification and referring to the accompanying drawings in which similar characters of reference represent corresponding parts in each of the several views:

In the drawings:

FIG. 1 is a schematic side elevational view, showing the chair ascending a stair and showing the chair leveling skid in operative and retractive positions.

FIG. 1A is a fragmentary enlarged side elevation of a portion of FIG. 1, showing modifications of the leveling device.

FIG. 2 is a schematic view of the chain drive for the ground engaging wheel in enlarged scale, as view along the line 2--2 of FIG. 3.

FIG. 3 is a vertical sectional view, taken substantially along the line 3-3 of FIG. 2.

' FIG. 4 is .a sectional view taken substantially along line 44 of FIG. 3.

FIG. 5 is a view similar to FIG. 3 of a modification wherein gears are used instead of chains and sprockets.

FIG. 6 is a fragmentary side view showing a modification of a portion of FIG. 1.

FIG. 1 of the accompanying drawings shows a conventional, schematically illustrated wheel chair 11, having a seat 12, back 13, arm rest 14, foot support 16, and nonpower driven ground-engaging wheels 17 mounted on brackets 18, depending from the front of the under-carriage 19 of the chair, all as well understood in this art. It will be understood that the present invention may be used with a wide variety of different chair or other vehicle constructions.

In accordance with the present invention, a main horizontal transverse axle 21 is rotatively mounted and supported from frame 19. Rotatable relative to axle 21 is a drive gear 24, having. external teeth which are engaged by pinion 26, which is driven by manual means or by a power source (not shown), such as an electric motor, gasoline motor, or other prime mover, The power source is reversible for forward or backward movement. Fixed todrive gear 24 is an internal ring gear 27. Meshing with internal gear 27 is a plurality of planet gears 28 (here shown as three, in number) which, in turn, mesh with sun gear 29, keyed by means of key 31.to axle 21. A single planet 28 may be used, if suitably mounted. Planet gears 28 are mounted on stub shafts 32 in vertical spider 33, which is concentric with but rotatable relative to shaft 21. Spider 33 carries a bearing 34 through which axle 21 passes. As here shown, spider 33 has three radial arms. A second spider'36, similar to spider 33, also having a bearing 37, may likewise be mounted on axle 21..

In the form of the invention herein illustrated, there are three ground engaging wheels 41, it being understood that more such wheels may be used. Thenumber of arms of spiders 33 or 36 should correspond to the number of spider wheels 41, Each wheel 41 has a central hub 42;

supported by bearings 43 on a shaft 44 which extends between the two spiders 33, 36. The periphery of wheel 41 may have a ground engaging tire 46. In normal travel, at least one wheel 41 is on the ground. On approaching an obstruction, two ofthe tires 46 engage the ground at one time. Each hub 42 carries sprocket 47. Keyed by means of key 48 to the axle 21 is sprocket 49. Chain 51 passes around the three sprockets 47, and also around sprocket 49, in the particular arrangement shown best in FIG. 2. In other words, the chain 51 passes around the rear of sprocket 49, and thence around the outside of all of the sprockets 47. All of the sprockets 47 turn in the opposite direction to sprocket 49.

In normal level ground operation, the prime mover turns gear 27 and causes axle 21 to rotate. Rotation of shaft 21 likewise causes rotation of sprocket 49 and chain 51 drives all three wheels 41. In this level ground operation of the chair, spiders 33, 36 remain stationary relative to the chair frame 19 because the resistance to rotation of the spiders is greater than the resistance to rotation of wheels 41 about shafts 44.

In ascending 'a stairway, the device 11 is turned in the direction shown in FIG. 1. The rearmost wheel 41a rests on stair tread 61. The direction of rotation of wheel 41a is counterclockwise for upward travel. When wheel 41a encounters stair riser 62, the wheel can no longer move horizontally rearwardly because of the obstruction. However, pinion 26 continues to turn although chain 51 stops as does sprocket 49 and thus sun 29 stops. Hence ring gear 27 causes planets 28 to revolve around the axis of shaft 21 as a center. This results in rotation of spiders 33, 36 about shaft 44a of wheel 41a as a center. Thus the shaft 44b of wheel 41b moves from the position of FIG. 1 along the are shown until wheel 41b rests upon the next tread 61a above original tread 61. This rotation of spiders 33, 36 is continued until level ground is reached, whereupon level ground operation is resumed. It will be understood that in descending stairs a reverse operation occurs.

To preserve the horizontal balance of chair 11 during ascending or descending, a skid 66 is used which slides along the corners where the tread 61 and risers 62 meet and supports the forward end of the chair. Skid 66 is mounted on an elongated arm 67 pivoted by means of brackets 69 about the axis of shaft 21. In a preferred form of the invention, a single arm 67 is used and said arm is located centrally relative to the sides of the chair. Arm 67 extends upward and rearward beyond shaft 21 and is connected to extensible link 71, which in this form of the invention comprises a hydraulic or pneumatic pis ton 72 and cylinder 73, the upper end of which is pivotally connected to the top of back 13 so that by extending and contracting rod 72 the angularity of arm 67 may be adjusted. A different form of adjustment is shown in fragmentary form of FIG. 6, wherein a screw 76 is rotated manually or by means of an electric motor 77 pivoted to back 13 and engaging nut 78 pivotally attached to arm 67 and similarly adjusting the position of arm 67 relative to a horizontal plane.

The lower end of arm 67 is preferably telescopically arranged for extension and contraction, so that when the vehicle is not used in negotiating stairs the arm may be retracted under the chair where it is not in the way. In the form of the invention herein shown, the extension 81 of arm 67 is extended manually and a lock pin 82 used to hold extension 81 in projected position. It will be apparent that pneumatic, hydraulic, or mechanical means may be used to extend or retract extension 81 as required. The lower end of extension 81 is provided with a downward extending bracket 83 carrying a shaft 84 at its lower end. Pivoting on shaft 84 is a spider 86 having three or more legs 87 and here shown as having four legs 87. Each leg 87 may be offset relative to the axis of shaft 84 by a fixed distance. Legs 87 are equi-angularly spaced.

' Rotatably mounted on each of legs 87 is a plurality of radially spaced rollers 88 which are of small diameter. When the vehicle is mounting stairs, extension 81 is projected and adjusted to the solid line position shown in FIG. 1. As the vehicle climbs, one of the outermost rollers 88 comes in contact with the riser of the step 62. The spider 86 then pivots about roller 88, and thus rotates about the axis of shaft 84 until roller 90 comes in contact with the overhanging lip 91 of the step (or the corner of the step where no lip is used) and until the" leading roller on the preceding arm comes in contact with the stair tread 61. In the cases of a step which has a lip 91, roller 88 now moves clear of riser 62. Due to the upward motion of the vehicle, spider 86 continues to rotate about shaft 84, and roller 90 moves up and over the edge of lip 91 so that roller 89 is in turn brought into contact with the face of the lip, and so on until roller 88 is in turn brought into contact with the lip. It should be understood that rollers 88, 89 and 90 are of such size, number and so placed adjacent to each other that the movement of these rollers onto and over the stair lip is substantially smooth. Spider 86 then continues to rotate and then moves backwards across stair tread 61 until the next step is encountered, whereupon the previously described process is repeated.

The arrangement of rollers 88 to 90 on the various legs 87 of the spider 84 will ordinarily be identical, but in order to illustrate certain modifications of the invention several of legs 87 are different from the remaining legs. Thus in leg 87a, a belt 92 passes around all of the rollers 88a to 90a on that particular leg. The use of belt 92 prevents the lip 91 or edge of the step from catching between the rollers and hence further augments the safety effect of the use of the rollers. It is desirable that the lowermost roller be free to rotate in a direction opposite the inner rollers to clear the overhanging step lip. Hence on leg 87!), the belt 92a passes around the inner rollers 89b and 90b but does not pass around the outer roller 88!). In leg 87c, belt 920 passes around all rollers 880 to 900 (as in leg 87a); however, a large diameter secondary roller 94 is provided on the same shaft as outermost roller 88c and is freely rotatable relative thereto and hence functions in a manner similar to roller 8811.

Instead of a single skid 66, a plurality of arms similar to arm 67 may be used and each arm may be provided with a spider device similar to 86.

The form of the invention shown in FIG. 5 is similar to that in the preceding modification, and since many of elements are similar, the same reference numerals followed by the subscript d are used throughout. In this form of the invention, however, the chain drive is eliminated. Each hub 42d carries a gear 76 which meshes with a central gear 77 which is keyed to shaft 21d by means of key 78. In other respects, the drive is similar and the climbing and descending of stairs are identical.

Although the foregoing invention has been described in some detail, by way of illustration and example for purposes of clarity of understanding, it is understod that certain changes and modifications may be practiced within the spirit of the invention and scope of the appended claims.

What is claimed is:

1. In a device for ascending or descending stair-like obstructions to level progress, a frame, an axle rotatably mounted in said frame adjacent one end, a planetary drive comprising a sun fixed on said axle, at least one planet meshing with said sun and an outer ring gear meshing with said planet, means for turning said ring gear, mounting means rotatable relative to said axle, at least three ground engaging wheels rotatably and equiang-ularly mounted in said mounting means, and drive means for rotating each of said wheels from said axle, at least one said wheel being positioned to rest on the ground when said device is traveling on level ground, said mounting means and said axle being free to rotate about the axis of said one wheel as a center when said one wheel encounters an obstruction to level progress.

2. A device according to claim 1, which further comprises leveling means pivotally mounted on said frame and projecting beyond the end of said frame opposite said axle, and means for adjusting the position of said leveling means to support said frame level while said mounting means and said axle rotate.

3. A device according to claim 2, in which said leveling means comprises an extensible arm and skid means on the outer end of said arm.

. 4. A device according to claim 3, in which said skid comprises a spider having a plurality of angularly spaced legs, means rotatably mounting said spider on said arm, and a plurality of rollers on each said leg of said spider.

5. A device according to claim 4, which further comprises a belt on each said leg encircling at least some said rollers.

6. A device according to claim 1, in which said drive means comprises a first sprocket fixed on said axle, a second sprocket fixed for rotation with each said Wheel and a chain around each of said sprockets to drive each said second sprocket in the opposite direction to said first sprocket.

7. A device according to claim 1, in which said drive means comprises a first gear fixed on said axle, and second gears each fixed for rotation with one of said wheels, all of said second gears turned by said first gear.

8. A device according to claim 1, in which each of said planets is rotatably mounted in said mounting means.

9. A self-propelled wheel chair comprising a frame, a front wheel at the front of the chair, an axle rotatably mounted in said frame at the back of said chair, a prime mover on said chair, a sun on said axle, planets meshing with said sun, an internal ring gear around said planets and meshing therewith, means for driving said internal ring gear from said prime mover and thence driving said axle, at least one spider freely rotatable about said axle, said planets rotatably mounted in said spider, at least three shafts equi-angularly mounted around said spider, ground engaging wheels on each said shaft, and drive means for turning said shafts and ground engaging wheels in unison from said axle, said spider turning rearwardly and upwardly about the axis of the rearmost ground engaging wheel when said rearmost ground engaging wheel encounters an obstruction to rearward level progress.

10. A wheel chair according to claim 9, which further comprises a forward extending lever having a skid, means pivotally mounting said lever on said frame, and means for adjusting the angle of said lever so that said skid rests on a stationary surface to maintain said frame level.

11. A claim according to claim 10, in which said skid comprises a spider having a plurality of angularly spaced legs, means rotatably mounting said spider on the forward end of said lever, and a plurality of rollers on each said leg of said spider, said rollers spaced along the length of said legs.

12. A wheel chair according to claim 10, in which said drive means comprises a first sprocket on said axle, second sprockets on each said shaft and a chain around the back of said first sprocket and around each said second sprocket to turn all said ground engaging wheels in the same direction.

13. A wheel chair according to claim 10, in which said drive means comprises a first gear fixed on said axle, and second gears on each said shaft, said first gear turning all said second gears.

14. A leveling device for a stair-climbing vehicle comprising an extensible arm, means pivotally mounting said arm on said vehicle, means for adjusting the angle of said arm relative to said vehicle, a spider rotatably mounted on the outer end of said arm and having a plurality of angularly spaced legs, and a plurality of rollers spaced from each other and mounted on each said leg.

15. A device according to claim 14, in which each said leg is angularly disposed relative to a diameter through the axis of mounting of said spider.

16. A device according to claim 14, which further comprises a belt on each said leg encircling at least some of said rollers.

17. In a stair climbing device, an arm, a spider rotatably mounted on said arm, said N spider having a plurality of angularly spaced legs, and a plurality of rollers spaced from each other and mounted on each said leg.

References Cited by the Examiner UNITED STATES PATENTS 2,742,973 4/ 1956 Johannesen -8 2,931,449 4/1960 King 180-8 2,933,323 4/1960 Webber 280--5.26 X 3,214,184 10/1965 Kemm 2805.26 3,241,848 3/1966 Flory 280-626 r o t euar mw wart": 

1. IN A DEVICE FOR ASCENDING OR DECENDING STAIR-LIKE OBSTRUCTIONS TO LEVEL PROGRESS, A FRAME, AN AXLE ROTATABLY MOUNTED IN SAID FRAME ADJACENT ONE END, A PLANETARY DRIVE COMPRISING A SUN FIXED ON SAID AXLE, AT LEAST ONE PLANET MESHING WITH SAID SUN AND AN OUTER RING GEAR MESHING WITH SAID PLANET, MEANS FOR TURNING SAID RING GEAR, MOUNTING MEANS ROTATABLE RELATIVE TO SAID AXLE, AT LEAST THREE GROIUND ENGAGING WHEELS ROTATABLY AND EQUIANGULARLY MOUNTED IN SAID MOUNTING MEANS, AND DRIVE MEANS FOR ROTATING EACH OF SAID WHEELS FROM SAID AXLE, AT LEAST ONE SAID WHEEL BEING POSITIONED TO REST ON THE GROUND WHEN SAID DEVICES IS TRAVELING ON LEVEL GROUND, SAID MOUNTING MEANS AND SAID AXLE BEING FREE TO ROTATE ABOUT THE AXIS OF SAID ONE WHEEL AS A CENTER WHEN SAID ONE WHEEL ENCOUNTERS AN OBSTRUCTION TO LEVEL PROGRESS. 